Associations of physical activity, cardiorespiratory fitness and fatness with low-grade inflammation in adolescents: the AFINOS Study

Abstract

Objective: To examine the independent associations of objectively measured physical activity (PA), cardiorespiratory fitness (CRF) and fatness with low-grade inflammatory markers in adolescents. Design: Cross-sectional study in Spain. Subjects: A sample of 192 adolescents aged 13-17 years. Measurements: PA was assessed with an accelerometer for 7 days. A 20-m shuttle-run test was used to assess CRF. Skinfold thicknesses at six sites and WCs were measured. BMI was calculated from measured height and weight. C-reactive protein (CRP), interleukin-6 (IL-6) and complement factors C3 and C4 were assayed. The homeostasis model assessment of insulin resistance (HOMA-IR) was calculated from glucose and insulin. Regression analysis adjusted for potential confounders and HOMA-IR was used to determine the associations between PA, CRF and fatness with low-grade inflammatory markers. Results: Total PA, vigorous PA and MVPA were positively associated with CRF (r ¼ 0.25-0.48), whereas vigorous PA was negatively associated with skinfolds (r ¼ À0.27). CRF was inversely associated with fatness, (r ¼ À0.30 to À0.48). CRF and fatness were inversely and positively associated with HOMA-IR (r ¼ À0.16 and 0.21, respectively). PA variables were not independently associated with inflammatory markers. CRF and fatness were inversely and positively associated with CRP, C3 and C4, respectively. Only body fat explained a relevant amount of the variance of the model in CRP (4%) and C4 (19%), whereas CRP and body fat jointly explained the variance in C3 (25%). All these observations were independent of HOMA-IR. Conclusions: These findings support the key role of CRF and fatness on low-grade inflammation, as well as the possible indirect role of habitual PA through CRF and body fat in adolescents.

Proteína C-reativa, atividade física e aptidão cardiorrespiratória em adolescentes portugueses: um estudo transversal

“…Significant associations between CRP and BMI were also found in both genders (preliminary data not shown), which is in accordance with other studies 24,25,29,30,32 . The current literature shows body fat as the main influencing factor of CRP concentration 37 .…”

“…These findings are consistent with those reported in the NHANES study, with 1,643 children and adolescents, age 6 to 17 years, in which no association was found between CRP and PA measured objectively 34 . Similarly, in two other recent studies, no association was found between PA measured objectively and CRP 21,32 . However, Parrett et al 24 explored a joint association between body fat, CRP and PA (measured by pedometers) and found a negative association (r = -0.49, p < 0.05) in a group of 44 children.…”

“…However, Owen et al 22 , in the CHASE study, reported a strong association between PA measured objectively and CRP in a sample of Caucasian-European, Southern-Asiatic, and Afro-Caribbean children. While some studies with young subjects find negative associations between PA or cardiorespiratory fitness and CRP 2,22,23,24,25,26,27 , others do not 21,28,29,30,31,32,33,34,35,36 . Moreover, in many of these studies, the results are not presented independently from the body mass index (BMI), a potentially confounding variable of the relationship between CRP and PA or cardiorespiratory fitness 37 .…”

Relationships Among Indicators of Fitness, Fatness and Cardiovascular Disease Risk Factors in Adolescents

“…Though some have noted a significant association between cardiorespiratory fitness and adiponectin (Nemet et al, 2003), the authors failed to consider the effects of adiposity within their analysis and involved younger participants. Others have found no significant associations between cardiorespiratory fitness and adiponectin (McVean et al, 2009) or have found an inverse association that was not in the expected direction for health (Martinez-Gomez et al, 2010).…”

Malnutrition and Inflammation

“…Environmental factors such as physical activity may counteract the consequences of excessive body fat. Cardiorespiratory fitness has been inversely associated with serum levels of inflammatory markers such as CRP and complement factors C3 and C4, all of which were positively associated with body fat (Martínez-Gómez et al, 2010). An intervention programme carried out on overweight/obese adolescents (aged 13-16 years) to promote a healthy lifestyle and lose weight (the EVASYON study), resulted in decreased serum levels of leptin and several cytokines (IL-8, IL-10 and TNF-), without affecting those of adiponectin, total peptide YY, or even insulin, and these changes seemed to depend on physical activity and fitness (Romeo et al, 2011).…”